A leading-order comparison between fluid-gravity and membrane-gravity dualities

In this note, we have compared two different perturbation techniques that are used to generate dynamical black-brane solutions to Einstein's equations in the presence of negative cosmological constant. One is the 'derivative expansion', where the gravity solutions are in one-to-one correspondence with the solutions of relativistic Navier-Stokes equation. The second is the expansion in terms of inverse power of space-time dimensions and here the gravity solutions are dual to a co-dimension one dynamical membrane, embedded in AdS space and coupled to a velocity field. We have shown that in a large number of space-time dimensions, there exists an overlap regime between these two perturbation techniques and we matched the two gravity solutions along with their dual systems up to the first non-trivial order in the expansion parameter on both sides.